Electrostatic sheet-perforating machine



y 1951 L. J. MONTY ELECTROSTATIC SHEETPERFORATING MACHINE 2 Sheets-Sheet1 Leo JZMo Filed Jan. 8, 1949 May 15 1951 L. J. MONTY ELECTROSTATICSHEET-PERFORATING MACHTNE Filed Jan. 8, 1949 2 Sheets-She et 2 TO RAIL34 Isa 29211302 To FRAME Zea Jib (b22350,

ayll/aan/vsmdtix fwwa/m FIG 5 flifomneys Patented May 15, 1951 ELECTROSTATIC SHEET-PERFORATING MACHINE Leo J. Monty,

Reading,

Mass., assignor to Goodall-Sanford, Inc., Sanford, Maine, a corporationof Maine Application January 8, 1949, Serial No. 69,891

Claims. 1

This invention has for its object to provide a machine for efiiciently,accurately, and rapidly electrostatically perforating non-conductive ordi-electric sheet material and particularly coated fabrics such aslargely employed for upholstery purposes.

The object of the invention is further to provide such a machine actingto produce the perforations without injury to the fabric, but of acharacter and size to render the fabric sunciently porous to breathe asthat term is employed in the upholstery and allied arts, while at thesame time the perforations are so minute as to be inconspicuous.

The object of the invention is further, and this is a most importantfeature, to enable the perforations to be formed in straight parallelrows spaced to any desired extent and extending transversely of thesheet of material. This, among other things, enables the number ofperforations per unit of area to be controlled with exactness throughoutthe entire run of fabric.

The invention has for its further object to enable the perforatingoperation to be carried on at high speed with the perforations uniformlyspaced in uniformly spaced parallel rows, and with each spark dischargeformed under the same conditions, thus insuring the advantages of theelectrostatic perforating operation to be secured.

Ihese and other objects and features of the invention will appear morefully from the accompanying description and drawings and Will beparticularly pointed out in the claims.

The drawings illustrate a preferred embodi- 1 ment of the inventiondesigned for the perforating of coated fabric, such as employed forupholstery and similar purposes, in which the fabric is of a width onthe order of 54" and is handled in rolls of fifty yards or thereabouts,but the size of the machine and the Width and length of the sheetmaterial operated upon depends upon the particular conditions.

In the drawings,

Fig. 1 is a top plan view of the machine with a piece of fabric passingthrough;

Fig. 2 is a front elevation of the machine with some parts broken awayand some diagrammatically indicated;

Fig. 3 is a transverse vertical section taken on the line 3-3 of Fig. 2,looking toward the right;

Fig. 4 is a view on a smaller scale generally similar to Fig. 3, butillustrating a multisection machine; and,

Fig. 5 is a diagram illustrating a simple type of means for supplying tothe machine the electric current for effecting the electric sparkdischarges.

The advantages of the electrostatic perforating of sheet material ofvarious kinds are well recognized. The perforations formed in thismanner, however minute they may be, still present, due to the burningoperation, smooth finished wall openings enabling the passage of air orthe breathing effect desired to be secured at all times.

While the machine of this invention may be employed with a wide varietyof sheet material, it is particularly designed for use in theperforation of coated fabrics, such as employed in upholstery, Where itis important that a uniform breathing action to a controlled amount maybe secured continuously and consistently in commercial operations. Animportant requirement in the securing of this result is that the numberof perforations per unit area shall be uniform throughout and capable ofadjustment as the particular character of the sheet material and the useto which it is to be put may deter mine.

In order to effect this result the machine of this invention operates toform the perforations in parallel, preferably straight, rows uniformlyspaced to any desired amount, and extending transversely of the sheet ofthe material.

The essential feature of the machine for se curing the required resultsis the employment of two endless conveyers supporting and carrying theelectrodes with one conveyer mounted above and one below the plane oftravel of the sheet of material adjacent a point where it is firmlysupported and with the lower run of the upper conveyer and the upper runof the lower conveyer guided to maintain the electrodes while on theseruns in opposition and uniformly spaced so as to secure a uniformsparking action.

It will be seen that since the electrodes travel rectilinearly at auniform speed, and the sheet of material travels in a direction at rightangles to the path of travel of the electrodes, that the rows ofperforations will always be parallel and extend at an angle to the edgesof the sheet depending upon the relative speeds, that the rows willextend in straight lines when the electrodes and the sheet travel at thesame speed, and that the spaces between the rows will depend upon thespacing of the electrodes on the conveyers and the relative speedsemployed. The spacing of the perforations in each row will dependprimarily upon the spacing of the electrodes on the conveyers, the speedof travel of the conveyers, and the speed of travel of the sheet.

Referring now to the specific embodiment of the invention illustratedthe machine comprises a suitable supporting frame including the legs Iand girders .2. A roll 3 of the sheet material 4 to be perforated issupported on a shaft 5 at the rear of the machine. Therefrom the sheetmaterial passes forward over an idler roll 6, thence over a rectangularsupport, thenceover a second idler and is wound up by a driven roll 8into a roll i} at the front of the machine. Any suitable means, such asthe usual belt drive or independent motor, may be provided for drivingthe roll 8 which feeds the sheet through the machine at the requiredspeed.

The rectilinear support over which the sheet 4 passes between the idlerrolls E and l is for the purpose of maintaining the sheet taut in aplane extending transversely of the machine. Preferably, and as shown,it comprises two rigid rectilinear rails it extending in closely spacedparallelism so that the sheet 4 is held by them taut in a plane.

The conveyers employed are preferably sprocket chains. The upperconveyer H at the left of the machine extends around the sprocket wheel:2 on the shaft l3 and at the right around a sprocket wheel 14 carriedby the shaft 5. The lower conveyer it at the left extends around thesprocket wheel ll carried by the shaft l8 and the right around thesprocket wheeel l9 carried by the shaft 28. The shafts i5 and 2c areidlers but the shafts i3 and i8 carry intermeshing gears and 22. Theshaft i3 is shown as driven by a motor 23 acting through a suitabletransmission mechanism 24 so that the speed of the conveyors may becontrolled as desired.

Since the electrodes must be maintained uniformly spaced during theperforating operation it is essential that the lower run of the upperconveyer and the upper run of the lower conveyor shall be accuratelymaintained in uniformly spaced parallelism and parallel with the planeof travel of the sheet. This is easily effected in the case of the lowerconveyer by providing a rigid transverse supporting rail 25 upon whichthe conveyor chain rests and travels while on its upper run. In the caseof the upper conveyor a rigid rail 26, shown of L-shaped form, issecured to a rigid channel beam 2? extending transversely of the machineand suitably supported, as indicated, from the platform 2. The lower runof the conveyer ll rides on this rail 25 i and is preferably held incontact therewith by a series of idler sprocket wheels 28inounted on andextending forward from the beam 2'1.

An electrode 29 is secured to the lower conveyer 6 to project therefromand is shown as a screw longitudinally adjustable in a block 33 securedto one link of the chain forming the cunveyer. The cooperating electrode3! is similarly shown as a screw longitudinally adjustable in a blockmounted on and projecting forwardly from one of the links of the chainconstituting the conveyor i l. The electrode 3! extends into an angularsuppor 33 which, while on the lower run of the conveyer, rides upon theflange of an angle iron 3 extending in parallelism with the rail 26 andsupported from brackets 35 secured to the channel beam 27. The angleiron 3% is an electrically conducting rail and is therefore suitablyinsulated from the machine as, for example, by forming the supports 36of Bakelite.

So also the block is of suitable insulating material. Hence theelectrode 26 is insulated from the machine except when the angularsupport 33 is in engagement with the rail 34 or an extension thereof.

The electrodes 28 and 3| are thus carried during their passage acrossthe sheet material directly opposite each other, held spaced at apredetermined constant distance. Any suitable and well known means maybe employed for causing the sparking discharge between the electrodeswith either alternating or direct current regulated by transformers,resistances, and condom-- and with the required frequency obtainedeither from the cycles of the alternating current or from theinterruption of the direct current, as well understood in the art.Preferably the standard alternating current is employed with a condenserin the secondary circuit and a volt i eter therein for determining thetransformed current, all as indicated in the diagram in Fig. 5. Onebranch of the secondary circuit is connected to the rail 34 which isinsulated from the frame while the other branch is connected to theframe of the machine or the rail 25 which is secured to the frame.

The conveyers are shown as traveling in the d rection indicated by thearrows 3i and the rail .3

at the leading end is shown as having a curved :rtension 32 guiding theelectrode 3! adjacent to a similarly curved plate secured to the frameso that sparking will begin shortly before the two electrodes come intoalinement and thus insuring the sparking action beginning before theelectrodes pass over the sheet of material.

The machine has been described with a single of conveyors and with asingle pair of cora ug elec rodes, one on each conveyer, and this willbe sun" ent for a large clas of work, but the speed of operation may beincreased both by increasing the number of pairs of electrodes on theconveyors, by increasing the number of pairs of conveyers, or by both. Asecond pair of elect" des is indicated at 38 and ti in Fig. 2 and Fig. 4is shown a machine in which the number of pairs of ccnveyers isincreased, three such pairs of conveyors being illustrated as anexxnple.

It is unnecessary to describe in detail the multi section constructionshown in Fig. 4 because it involves merely a duplication of theconveyers and their supports, the electrodes, etc. already described. Asshown, the sheet of material 5 travels from the idler E31 over aplurality of rectangular supports 52 and thence over the idler Threelower conveyors 54 are shown carrying the electrodes 55, all guided andoperating in the construction already described. So also three upperconveyors 59 carrying the electrode El are shown, all guided andoperating already described. The right hand sprocket wheels 58 areecured to a single shaft 59 corresponding to the shaft 2i! extended andsimilarly e upper sprocket wheels fill are secured to a sin s: shaft (iicorresponding to the shaft [5 extended. The drive at the left hand endof the machine not illustrated as it merely involves an extension of theshafts l3 and i8 and the duplication of the sprocket wheels thereon.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

l. A machine for electrostatically perforating sheet material comprisinga rectilinear support, means for feeding sheet material across thesupport in contact therewith, rectilinear guides adjacent the supportextending parallel therewith one above and one below the plane of thesheet travel, a pair of endless conveyers one above and one below saidplane, with the lower run of the upper conveyer guided by the upperguide and the upper run of the lower conveyer guided by the lower guide,a pair of electrodes one projecting from each conveyer maintained bysaid conveyers and by said guides in opposition and uniformly spacedwhile on said runs, means for driving the conveyers, and means forcausing predetermined electric spark discharges between the electrodeswhile on said runs.

2. A machine for electrostatically perforating sheet material as definedin claim I, in which the means for feeding the sheet material acts tofeed the same at a uniform speed and the means for driving the conveyersacts to drive them at a uniform speed thus to insure the perforations toextend in parallel equispaced rows.

3. A machine for electrostatically perforating sheet material comprisinga rectilinear support, means for feeding the sheet material across thesupport in contact therewith, a pair of endless conveyers one above andone below the path of the sheet material, means for driving theconveyers at the same speed, means for maintaining the lower run of theupper conveyer and the upper run of the lower conveyer in paths parallelto the support, a pair of electrodes one projecting from each conveyermaintained in cooperative relation while on said runs, and means forcausing predetermined electric spark discharges between the electrodeswhileon said runs.

4. A machine for electrostatically perforating sheet material as definedin claim 1, in which the upper electrode is mounted in a blockprojecting forward from the upper conveyer and is insulated from theconveyer, together with a current-conducting rail extending parallel tothe upper guide insulated from the machine and upon which the upperelectrode rides while upon the lower run.

5. A machine for electrostatically perforating sheet material comprisinga plurality of parallel rectilinear supports, means for feeding thesheet material successively across the supports in contact therewith, apair of endless conveyers i line with each space between the supports,with one conveyer of each pair above and one below the path of the sheetmaterial, rectilinear guides for the lower run of each upper conveyerand the upper run of each lower conveyer, a pair of electrodes for eachpair of conveyers, one projecting from each conveyer of the pair andmaintained by said conveyers and their guides in 0pposition anduniformly spaced while on said runs, means for driving simultaneouslyall the conveyers, and means for causing predetermined spark dischargesbetween the several pairs of electrodes while on said runs.

LEO J. MONTY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 736,571 Ball Aug. 18, 19031,898,014 Krumholz Feb. 21, 1933 2,011,645 Miller Aug. 20, 19352,277,942 Anderson Mar. 31, 1942 2,365,576 Meaker et a1 Dec. 19, 19442,372,508 Meaker Mar. 27, 1945 2,388,069 Meaker et al Oct. 30, 1945

